XS

Element: xs

If this element is present with valid configuration, the macroscopic dielectric function and related spectroscopic quantities in the linear regime are calculated through either time-dependent DFT (TDDFT) or the Bethe-Salpeter equation (BSE).

contains:	storeexcitons (optional) writeexcitons (optional) writekpathweights (optional) excitonPlot (optional) realTimeTDDFT (optional) tddft (optional) screening (optional) BSE (optional) fastBSE (optional) transitions (optional) qpointset (optional) tetra (optional) energywindow (optional) plan (optional)
XPath:	/input/xs

This element allows for specification of the following attributes: xstype (required), bfieldc, broad, dbglev, dfoffdiag, dogroundstate, emattype, emaxdf, epsdfde, fastpmat, gqmax, gqmaxtype, h5fname, h5gname, lmaxapwwf, lmaxemat, maxscl, nempty, ngridk, ngridq, nosym, pwmat, reducek, reduceq, rgkmax, scissor, skipgnd, swidth, tappinfo, tevout, vkloff, writexsgrids

Attribute: bfieldc

This attribute overrides the homonym attribute from the groundstate/spin element.

Type:	vect3d
Default:	"0.0d0 0.0d0 0.0d0 "
Use:	optional
XPath:	/input/xs/@bfieldc

Attribute: broad

Lorentzian broadening for all spectra

Type:	fortrandouble
Default:	"0.01d0"
Use:	optional
Unit:	Hartree
XPath:	/input/xs/@broad

Attribute: dbglev

Debugging level. Any value ${ > 0 }$ will produce additional debug output. The large the value, the more information is output.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/@dbglev

Attribute: dfoffdiag

"true" if also off-diagonal tensor elements for the interacting response function are to be calculated.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/@dfoffdiag

Attribute: dogroundstate

Decides if the ground state is calculated starting from scratch or using the densities from file.

Type:	choose from: fromscratch fromfile
Default:	"fromfile"
Use:	optional
XPath:	/input/xs/@dogroundstate

Attribute: emattype

Type of matrix element generation (band-combinations). Should only be referenced for experimental features.

Type:	integer
Default:	"1"
Use:	optional
XPath:	/input/xs/@emattype

Attribute: emaxdf

Energy cutoff for the unoccupied states in the Kohn-Sham response function and screening. This parameter ensures a cutoff at the specified energy and is defined in addition to the nempty parameter.

Type:	fortrandouble
Default:	"1.0d10"
Use:	optional
XPath:	/input/xs/@emaxdf

Attribute: epsdfde

The smallest energy difference for which the square of its inverse will be considered in the Kohn-Sham response function.

Type:	fortrandouble
Default:	"1.0d-8"
Use:	optional
Unit:	Hartree
XPath:	/input/xs/@epsdfde

Attribute: fastpmat

If set to "true", a fast method to calculate APW-lo, lo-APW and lo-lo parts of the momentum matrix elements in the muffin-tin is used.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/@fastpmat

Attribute: gqmax

${\bf |G+q|}$ cutoff for Kohn-Sham response function, screening and for expansion of Coulomb potential

Type:	fortrandouble
Default:	"0.0d0"
Use:	optional
XPath:	/input/xs/@gqmax

Attribute: gqmaxtype

Defines the way the gqmax cutoff is applied for the selection of the G-vectors. For $"|G+q|"$ G vectors are selected such that ${\bf G+q}$ lies within the gqmax cutoff. For $"|G|"$ G vectors are selected such that ${\bf G}$ lies within the gqmax cutoff.

Type:	choose from: |G+q| |G|
Default:	"|G+q|"
Use:	optional
XPath:	/input/xs/@gqmaxtype

Attribute: h5fname

Name of the hdf5 file to write the outputs to. Must end with .h5.

Type:	string
Default:	"bse_output.h5"
Use:	optional
XPath:	/input/xs/@h5fname

Attribute: h5gname

Name of the group in the hdf5 file to write the outputs to.

Type:	string
Default:	"/"
Use:	optional
XPath:	/input/xs/@h5gname

Attribute: lmaxapwwf

Maximum angular momentum for APW functions for q-dependent matrix elements.

Type:	integer
Default:	"-1"
Use:	optional
XPath:	/input/xs/@lmaxapwwf

Attribute: lmaxemat

Maximum angular momentum for Rayleigh expansion of ${\bf q}$-dependent plane wave factor.

Type:	integer
Default:	"3"
Use:	optional
XPath:	/input/xs/@lmaxemat

Attribute: maxscl

Upper limit of the self-consistency loop for the calculation of eigenvectors and eigenvalues from an existing ground-state calculation.

Type:	integer
Default:	"1"
Use:	optional
XPath:	/input/xs/@maxscl

Attribute: nempty

Number of empty states. This parameter determines the energy cutoff for the excitation spectra. For determining the number of states related to an energy cutoff, perform one iteration of a SCF calculation, setting nempty to a higher value and check the EIGVAL.OUT.

Type:	integer
Default:	"5"
Use:	optional
XPath:	/input/xs/@nempty

Attribute: ngridk

${\mathbf k}$-point grid sizes.

Type:	integertriple
Default:	"1 1 1"
Use:	optional
XPath:	/input/xs/@ngridk

Attribute: ngridq

q-point grid sizes.

Type:	integertriple
Default:	"1 1 1"
Use:	optional
XPath:	/input/xs/@ngridq

Attribute: nosym

nosym is "true" if no symmetry information should be used

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/@nosym

Attribute: pwmat

Algorithm for calculating matrix elements of plane waves. Matrix multiplications (mm) are better suited for small systems, while fast Fourier transforms (fft) are appropriate for large systems.

Type:	choose from: fft mm
Default:	"fft"
Use:	optional
XPath:	/input/xs/@pwmat

Attribute: reducek

reducek is "true" if ${\mathbf k}$-points are to be reduced (with crystal symmetries).

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/@reducek

Attribute: reduceq

reducek is "true" if q-points are to be reduced (with crystal symmetries).

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/@reduceq

Attribute: rgkmax

Smallest muffin-tin radius times gkmax. If set to zero (the default), this value defaults to the rgkmax set in the groundstate element.

Type:	fortrandouble
Default:	"0.0d0"
Use:	optional
XPath:	/input/xs/@rgkmax

Attribute: scissor

Scissors correction to correct the conduction band energies.

Type:	fortrandouble
Default:	"0.0d0"
Use:	optional
Unit:	Hartree
XPath:	/input/xs/@scissor

Attribute: skipgnd

If set to "true", recalculation of KS eigenvalues and eigenvectors is skipped.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/@skipgnd

Attribute: swidth

Width of the smooth approximation to the Dirac delta function (must be > 0).

Type:	fortrandouble
Default:	"0.001d0"
Use:	optional
Unit:	Hartree
XPath:	/input/xs/@swidth

Attribute: tappinfo

"true" to append info to output file.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/@tappinfo

Attribute: tevout

"true" if energy outputs are in eV.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/@tevout

Attribute: vkloff

The ${\mathbf k}$-point set offset. All ${\mathbf k}$-points of a regular ${\mathbf k}$-mesh (a mesh containing the Gamma point) are shifted by a constant vector given by $({\rm vkloff}_1/N_1, {\rm vkloff}_2/N_2, {\rm vkloff}_3/N_3)$, where $(N_1,N_2,N_3)$ is the division of the ${\mathbf k}$-point mesh. It should be selected such that all symmetries among the ${\mathbf k}$-points from the regular (non-shifted) mesh are broken. An exception is the case of optical spectra without local field effects where symmetries among ${\mathbf k}$-points are explicitly taken into account.

Type:	vect3d
Default:	"0.0d0 0.0d0 0.0d0 "
Use:	optional
XPath:	/input/xs/@vkloff

Attribute: writexsgrids

"true" to write out k, k+q, g, g+k, g+q grids to file.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/@writexsgrids

Attribute: xstype

Choice of excited state method: TDDFT, real-time TDDFT (RT-TDDFT) or BSE.

Type:	choose from: TDDFT BSE RT-TDDFT
Use:	required
XPath:	/input/xs/@xstype

Element: storeexcitons

When present this element allows to store the exciton components (BSE eigenvectors). The number of stored excitons starting from the lowest energy one is given by the attribute MaxNumberExcitons.

Type:	no content
XPath:	/input/xs/storeexcitons

This element allows for specification of the following attributes: MaxEnergyExcitons, MaxNumberExcitons, MinEnergyExcitons, MinNumberExcitons, selectenergy, useev

Attribute: MaxEnergyExcitons

Upper limit of the energy interval for the stored excitons.

Type:	fortrandouble
Default:	"100.0"
Use:	optional
XPath:	/input/xs/storeexcitons/@MaxEnergyExcitons

Attribute: MaxNumberExcitons

It represents the upper limit of the number of stored excitons.

Type:	integer
Default:	"10"
Use:	optional
XPath:	/input/xs/storeexcitons/@MaxNumberExcitons

Attribute: MinEnergyExcitons

Lower limit of the energy interval for the stored excitons.

Type:	fortrandouble
Default:	"0.0"
Use:	optional
XPath:	/input/xs/storeexcitons/@MinEnergyExcitons

Attribute: MinNumberExcitons

It represents the lower limit of the number of stored excitons.

Type:	integer
Default:	"1"
Use:	optional
XPath:	/input/xs/storeexcitons/@MinNumberExcitons

Attribute: selectenergy

Set to "true" if excitons within a specified energy interval shall be stored.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/storeexcitons/@selectenergy

Attribute: useev

"true" if energy input is in eV.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/storeexcitons/@useev

Element: writeexcitons

When present this element allows to write the stored exciton components (BSE eigenvectors) to ASCII files. The range of excitons must lie within the stored range given by the attributes in the element storeexcitons.

Type:	no content
XPath:	/input/xs/writeexcitons

This element allows for specification of the following attributes: MaxEnergyExcitons, MaxNumberExcitons, MinEnergyExcitons, MinNumberExcitons, abscutares, abscutres, selectenergy, useev

Attribute: MaxEnergyExcitons

Upper limit of the energy interval of the written excitons.

Type:	fortrandouble
Default:	"100.0"
Use:	optional
XPath:	/input/xs/writeexcitons/@MaxEnergyExcitons

Attribute: MaxNumberExcitons

It represents the upper limit of the number of written excitons.

Type:	integer
Default:	"10"
Use:	optional
XPath:	/input/xs/writeexcitons/@MaxNumberExcitons

Attribute: MinEnergyExcitons

Lower limit of the energy interval of the written excitons.

Type:	fortrandouble
Default:	"0.0"
Use:	optional
XPath:	/input/xs/writeexcitons/@MinEnergyExcitons

Attribute: MinNumberExcitons

It represents the lower limit of the number of written excitons.

Type:	integer
Default:	"1"
Use:	optional
XPath:	/input/xs/writeexcitons/@MinNumberExcitons

Attribute: abscutares

Cutoff interval for exciton eigenvector writeout (anit-resonant).

Type:	vect2d
Default:	"0.0d0 1.0d10"
Use:	optional
XPath:	/input/xs/writeexcitons/@abscutares

Attribute: abscutres

Cutoff interval for exciton eigenvector writeout (resonant).

Type:	vect2d
Default:	"0.0d0 1.0d10"
Use:	optional
XPath:	/input/xs/writeexcitons/@abscutres

Attribute: selectenergy

Set to "true" if excitons within a specified energy interval shall written.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/writeexcitons/@selectenergy

Attribute: useev

"true" if energy input is in eV.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/writeexcitons/@useev

Element: writekpathweights

This element configures the interpolation of the excitonic weights onto a banstructure path performend by the writekpathweights task.

Type:	no content
XPath:	/input/xs/writekpathweights

This element allows for specification of the following attributes: MaxEnergyExcitons, MaxNumberExcitons, MinEnergyExcitons, MinNumberExcitons, intorder, printgridweights, selectenergy, useev

Attribute: MaxEnergyExcitons

Upper limit of the energy interval of the written excitons.

Type:	fortrandouble
Default:	"100.0"
Use:	optional
XPath:	/input/xs/writekpathweights/@MaxEnergyExcitons

Attribute: MaxNumberExcitons

It represents the upper limit of the number of written excitons.

Type:	integer
Default:	"1"
Use:	optional
XPath:	/input/xs/writekpathweights/@MaxNumberExcitons

Attribute: MinEnergyExcitons

Lower limit of the energy interval of the written excitons.

Type:	fortrandouble
Default:	"0.0"
Use:	optional
XPath:	/input/xs/writekpathweights/@MinEnergyExcitons

Attribute: MinNumberExcitons

It represents the lower limit of the number of written excitons.

Type:	integer
Default:	"1"
Use:	optional
XPath:	/input/xs/writekpathweights/@MinNumberExcitons

Attribute: intorder

Spline order for the interpolation of the excitonic weights (polynomial order + 1).

Type:	integer
Default:	"2"
Use:	optional
XPath:	/input/xs/writekpathweights/@intorder

Attribute: printgridweights

"true" if the excitonic weights on the k-grid shall be printed to file.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/writekpathweights/@printgridweights

Attribute: selectenergy

Set to "true" if excitons within a specified energy interval shall be considered.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/writekpathweights/@selectenergy

Attribute: useev

"true" if energy input is in eV.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/writekpathweights/@useev

Element: excitonPlot

Parameters for the electron-hole visualization.

contains:	exciton (optional) hole (required) electron (required)
XPath:	/input/xs/excitonPlot

This element allows for specification of the following attributes: epstol

Attribute: epstol

Threshold value for selecting states which contribute to the exciton.

Type:	fortrandouble
Default:	"1.0d-4"
Use:	optional
XPath:	/input/xs/excitonPlot/@epstol

Element: exciton

Electron-hole pair descriptor.

Type:	no content
XPath:	/input/xs/excitonPlot/exciton

This element allows for specification of the following attributes: fix, lambda

Attribute: fix

Fix position (in lattice coordinates) either of the "hole" or "electron".

Type:	string
Default:	"hole"
Use:	optional
XPath:	/input/xs/excitonPlot/exciton/@fix

Attribute: lambda

The index of the stored exciton.

Type:	integer
Default:	"1"
Use:	optional
XPath:	/input/xs/excitonPlot/exciton/@lambda

Element: hole

For the exciton wavefunction visualization: Real space grid for the hole distribution.

contains:	plot1d (optional) plot2d (optional) plot3d (optional)
XPath:	/input/xs/excitonPlot/hole

Element: electron

For the exciton wavefunction visualization: Real space grid for the electron distribution.

contains:	plot1d (optional) plot2d (optional) plot3d (optional)
XPath:	/input/xs/excitonPlot/electron

Element: realTimeTDDFT

When present, this element triggers a real-time TDDFT calculation.

contains:	predictorCorrector (optional) screenshots (optional) laser (optional)
XPath:	/input/xs/realTimeTDDFT

This element allows for specification of the following attributes: TaylorOrder, calculateNExcitedElectrons, calculateTotalEnergy, endTime, forcePmatHermitian, normalizeWF, printAfterIterations, printTimingDetailed, printTimingGeneral, propagator, readPmatBasis, subtractJ0, timeStep, vectorPotentialSolver

Attribute: TaylorOrder

The order employed in the Taylor expansion (when it is used).

Type:	integer
Default:	"4"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@TaylorOrder

Attribute: calculateNExcitedElectrons

Calculates the number of excited electrons (per unit cell) at each time-step. Output: NEXC.OUT

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@calculateNExcitedElectrons

Attribute: calculateTotalEnergy

The total energy is calculated at each time-step and outputed in the file ETOT_RTTDDFT.OUT

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@calculateTotalEnergy

Attribute: endTime

Sets the end time, when the evolution stops.

Type:	fortrandouble
Default:	"100d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/@endTime

Attribute: forcePmatHermitian

When "true", the $x$, $y$ and $z$ components of the momentum matrix are forced to be Hermitian. This may be useful to avoid numerical noise.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@forcePmatHermitian

Attribute: normalizeWF

Normalizes the WFs after applying the time-evolution operator.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@normalizeWF

Attribute: printAfterIterations

Sets a number which determines how frequently data are printed to file. It means that the relevant data (JIND, AVEC, etc.) are accumulated and then printed at once.

Type:	integer
Default:	"50"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/@printAfterIterations

Attribute: printTimingDetailed

Prints detailed information about times required to evaluate some quantities. Only makes sense if printTimesGeneral="true"

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@printTimingDetailed

Attribute: printTimingGeneral

Prints general information about times required to evaluate some quantities.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@printTimingGeneral

Attribute: propagator

The method employed to propagate the WFs. Possible choices are: SE (simple exponential), EMR (exponential at midpoint rule), AETRS (approximate enforced time-reversal symmetry), CFM4 (Commutator-Free Magnus expansion of 4th order), EH (exponential using a basis of the hamiltonian-eigenvectors), EHM (same as before, but uses the hamiltonian at the midpoint), RK4 (Runge-Kutta of 4th order).

Type:	choose from: SE EMR AETRS CFM4 EH EHM RK4
Default:	"SE"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@propagator

Attribute: readPmatBasis

By setting it to "true", the momentum matrix elements are read from PMATBASIS.OUT (a previous calculation must have been done with the same relevant parameter for the basis, like rgkmax, k-grid, LOs, etc.).

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@readPmatBasis

Attribute: subtractJ0

Subtracts a residual current. This term ideally should be zero, actually it tends to zero when the number of k-points is increased. Subtracting J0 might help to eliminate numerical inaccuracies for not-so-dense k-grids.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@subtractJ0

Attribute: timeStep

Sets the time step of the time evolution.

Type:	fortrandouble
Default:	"0d1"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/@timeStep

Attribute: vectorPotentialSolver

The method employed to solve the differential equation of the vector potential. Possible choices are: euler, improvedeuler (using the Leapfrog integration method), midpoint (implicit midpoint method), rk4 (Runge-Kutta of 4th order).

Type:	choose from: euler improvedeuler midpoint rk4
Default:	"euler"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/@vectorPotentialSolver

Element: predictorCorrector

When present, this element triggers the predictor-corrector scheme (self-consistency in the propagation of the wavefunctions)

Type:	no content
XPath:	/input/xs/realTimeTDDFT/predictorCorrector

This element allows for specification of the following attributes: maxIterations maxIterations, tol
[att maxIterations]
[attpredictorCorrector maxIterations]

Attribute: maxIterations

The maximum number of iteractions spent in the predictor-corrector scheme.

Type:	integer
Default:	"10"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/predictorCorrector/maxIterations @ maxIterations

Attribute: tol

The required precision.

Type:	fortrandouble
Default:	"1d-5"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/predictorCorrector/@tol

Element: screenshots

Screenshots of the evolution.

Type:	no content
XPath:	/input/xs/realTimeTDDFT/screenshots

This element allows for specification of the following attributes: niter, printAbsProjCoeffs

Attribute: niter

At each 'niter' steps, outputs a 'screenshot'.

Type:	integer
Default:	"100"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/screenshots/@niter

Attribute: printAbsProjCoeffs

When set to true, calculates the projection of the current Kohn-Sham wavefunctions onto the groundstate ones and prints the absolute value of the projection coefficients. When set to false, the full complex number is printed.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/screenshots/@printAbsProjCoeffs

Element: laser

This element sets up the properties of the external field to applied to the sample.

contains:	kick (optional) trapCos (optional) sinSq (optional)
XPath:	/input/xs/realTimeTDDFT/laser

This element allows for specification of the following attributes: fieldType

Attribute: fieldType

This string forces to consider the laser field as the "total" or as the "external" field. The geometry of the sample with respect to the incident field is determinant in this case: for longitudinal geometry, use "external", for transversal, "total". If you do not know which one to use, we recommend to employ the default one.

Type:	choose from: total external
Default:	"total"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/laser/@fieldType

Element: kick

Specifies a delta kick.

Type:	no content
XPath:	/input/xs/realTimeTDDFT/laser/kick

This element allows for specification of the following attributes: amplitude, direction, t0, width

Attribute: amplitude

Sets the amplitude $E_0$ of the impulsive excitation $E_0\delta(t-t_0)$.

Type:	fortrandouble
Default:	"0.04d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/kick/@amplitude

Attribute: direction

The direction of the electric field of the laser pulse.

Type:	choose from: x y z
Default:	"z"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/laser/kick/@direction

Attribute: t0

Sets the time when an impulsive laser pulse is applied.

Type:	fortrandouble
Default:	"4d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/kick/@t0

Attribute: width

Sets the width of the impulsive excitation. When not set to zero, this allows to broaden the delta function.

Type:	fortrandouble
Default:	"4d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/kick/@width

Element: trapCos

Specifies a pulse given by $E=E_0\cos(\omega t + \phi)f(t)$, where $E_0$ is the amplitude, $\omega$ is the angular frequency, $\phi$ is the phase, and $f(t)$ is an envelope function of a trapezoidal kind. This function is zero up to the time $t_0$, then it rises linearly to one during a time equal to "rise time", it remains equal to one during a time equal to "width", after that, it takes the same "rise time" to fall to zero again.

Type:	no content
XPath:	/input/xs/realTimeTDDFT/laser/trapCos

This element allows for specification of the following attributes: amplitude, direction, omega, phase, riseTime, t0, width

Attribute: amplitude

Sets the amplitude $E_0$.

Type:	fortrandouble
Default:	"0.04d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/trapCos/@amplitude

Attribute: direction

The direction of the electric field of the laser pulse.

Type:	choose from: x y z
Default:	"z"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/laser/trapCos/@direction

Attribute: omega

Sets the angular frequency $\omega$.

Type:	fortrandouble
Default:	"1d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/trapCos/@omega

Attribute: phase

Phase $\phi$ of the laser.

Type:	fortrandouble
Default:	"0d0"
Use:	optional
Unit:	rad
XPath:	/input/xs/realTimeTDDFT/laser/trapCos/@phase

Attribute: riseTime

Rise time of the trapezoidal envelope.

Type:	fortrandouble
Default:	"1d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/trapCos/@riseTime

Attribute: t0

Time $t_0$ when the envelope starts to rise to one.

Type:	fortrandouble
Default:	"4d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/trapCos/@t0

Attribute: width

Sets the width of the trapezoid. During this time duration, envelope trapezoidal function remains equal to 1.

Type:	fortrandouble
Default:	"4d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/trapCos/@width

Element: sinSq

Specifies a pulse which vector potential is given by $A=A_0\cos(\omega t + \phi)f(t)$, where $A_0$ is the amplitude, $\omega$ is the angular frequency, $\phi$ is the phase, and $f(t)$ is an envelope function of a sin squared type. This function is zero up to the time $t_0$, then it assumes the shape of $sin^2(\pi (t-t_0)/T_{pulse})$ up to a time equal to $t_0+T_{pulse}$, after which, it becomes zero again.

Type:	no content
XPath:	/input/xs/realTimeTDDFT/laser/sinSq

This element allows for specification of the following attributes: amplitude, direction, omega, phase, pulseLength, t0

Attribute: amplitude

Sets the amplitude $A_0$.

Type:	fortrandouble
Default:	"1.37d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/sinSq/@amplitude

Attribute: direction

The direction of the electric field of the laser pulse.

Type:	choose from: x y z
Default:	"z"
Use:	optional
XPath:	/input/xs/realTimeTDDFT/laser/sinSq/@direction

Attribute: omega

Sets the angular frequency $\omega$.

Type:	fortrandouble
Default:	"1d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/sinSq/@omega

Attribute: phase

Phase $\phi$ of the laser.

Type:	fortrandouble
Default:	"0d0"
Use:	optional
Unit:	rad
XPath:	/input/xs/realTimeTDDFT/laser/sinSq/@phase

Attribute: pulseLength

The length of the pulse $T_{pulse}$.

Type:	fortrandouble
Default:	"250d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/sinSq/@pulseLength

Attribute: t0

Time $t_0$ when the envelope starts to assume the sin squared shape.

Type:	fortrandouble
Default:	"4d0"
Use:	optional
Unit:	atomic units
XPath:	/input/xs/realTimeTDDFT/laser/sinSq/@t0

Element: tddft

Type:	no content
XPath:	/input/xs/tddft

This element allows for specification of the following attributes: acont, ahc, alphalrc, alphalrcdyn, aresdf, aresfxc, betalrcdyn, do, drude, fxcbsesplit, fxctype, intraband, kerndiag, lindhard, lmaxalda, mdfqtype, nwacont, torddf, tordfxc

Attribute: acont

Set to "true" if analytic continuation from the imaginary axis to the real axis is to be performed.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tddft/@acont

Attribute: ahc

By setting it to "true", the anomalous Hall conductivity (AHC) term is included in the calculation of the dielectric tensor [see PRB 86, 125139 (2012)]. In this case, the MOKE.OUT output file is generated, containing the MOKE spectrum. This attribute only has effect when local field effects are neglected (gqmax=0) and q=0.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tddft/@ahc

Attribute: alphalrc

$\alpha$-parameter for the static long range contribution (LRC) model xc kernel.

Type:	fortrandouble
Default:	"0.0d0"
Use:	optional
XPath:	/input/xs/tddft/@alphalrc

Attribute: alphalrcdyn

$\alpha$-parameter for the dynamical long range contribution (LRC) model xc kernel.

Type:	fortrandouble
Default:	"0.0d0"
Use:	optional
XPath:	/input/xs/tddft/@alphalrcdyn

Attribute: aresdf

Set to "true" if to consider the anti-resonant part for the dielectric function.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/tddft/@aresdf

Attribute: aresfxc

Set to "true" if to consider the anti-resonant part for the MBPT derived xc-kernels.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/tddft/@aresfxc

Attribute: betalrcdyn

$\beta$-parameter for the dynamical long range contribution (LRC) model xc kernel.

Type:	fortrandouble
Use:	optional
XPath:	/input/xs/tddft/@betalrcdyn

Attribute: do

Decides if the TDDFT calculation is to be resumed starting from a new xc kernel or is to be skipped.

Type:	choose from: fromscratch fromkernel
Default:	"fromscratch"
Use:	optional
XPath:	/input/xs/tddft/@do

Attribute: drude

Parameters defining semiclassical Drude approximation to intraband term. The first value determines the plasma frequency $\omega_p$ and the second the inverse relaxation time $\omega_{\tau}$:$\chi_0^D=\frac{1}{\omega}\frac{\omega_p^2}{\omega+i\omega_{\tau}}$

Type:	vect2d
Default:	"0.0d0 0.0d0"
Use:	optional
XPath:	/input/xs/tddft/@drude

Attribute: fxcbsesplit

Split parameter for degeneracy in energy differences of MBPT derived xc kernels. See A. Marini, Phys. Rev. Lett., 91, (2003) 256402.

Type:	fortrandouble
Default:	"1.0d-5"
Use:	optional
Unit:	Hartree
XPath:	/input/xs/tddft/@fxcbsesplit

Attribute: fxctype

Defines which xc kernel is to be used. Examples on the use of the different kernels can be found online on the Tutorial "TDDFT Calculations with Different Kernels" on www.exciting-code.org. In the options indicated below, if the suffix "_NLF" is present, then local-field effects are neglected (scalar kernel). Otherwise the kernel is a matrix of the size of the number of $\mathbf{G}$-vectors, whose diagonal elements are all equal. The available kernels $f_{xc}$ are:

• "RPA" - Random-phase approximation kernel. $f_{xc}=0$
• "LRCstatic[_NLF]" - Long-range correction kernel.

(1)

\begin{align} f_{xc}=-\frac{\alpha}{\mathbf{q}^2}. \end{align}

See S. Botti et al., Phys. Rev. B 69, 155112 (2004)

• "LRCdyn[_NLF]" - Dynamical long-range correction kernel.

(2)

\begin{align} f_{xc}=-\frac{\alpha+\beta \omega^2}{\mathbf{q}^2} \end{align}

with $\alpha$ given by the value of alphalrcdyn and $\beta$ given by the value of betalrcdyn. See S. Botti et al., Phys. Rev. B 72, 125203 (2005)

• "ALDA" - Adiabatic LDA kernel.

(3)

\begin{align} f_{xc}(\mathbf{r},\mathbf{r}',t-t')=\frac{\delta V_{xc}(\mathbf{r})}{\delta n(\mathbf{r}')}\delta(t-t'). \end{align}

In this implementation, $V_{xc}(\mathbf{r})$ is the spin-unpolarised exchange-correlation potential corresponding to the Perdew-Wang parameterisation of Ceperley-Alder's Monte-Carlo data (see Phys. Rev. B 45, 13244 (1992) and Phys. Rev. Lett. 45, 566 (1980)).

• "MB1[_NLF]" - BSE derived xc kernel. See L. Reining et al., Phys. Rev. Lett. 88, 066404 (2002) and A. Marini et al., Phys. Rev. Lett. 91, 256402 (2003).
• "BO" - Bootstrap kernel.

(4)

\begin{align} f_{xc}=\frac{\varepsilon^{-1}(\omega=0)}{\chi_{00}(\omega=0)}. \end{align}

See S. Sharma et al., Phys. Rev. Lett. 107, 186401 (2011).

• "BO_SCALAR" - Scalar version of the bootstrap kernel. $f_{xc}=\left[\varepsilon_M(\omega=0)\chi_{00}(\omega=0)\right]^{-1}$. See S. Sharma et al., Phys. Rev. Lett. 107, 186401 (2011).
• "RBO" - RPA bootstrap kernel. $f_{xc}=\left[\varepsilon^{RPA}_M(\omega=0)\overline{\chi}_{00}^{RPA}(\omega=0)\right]^{-1}$. See S. Rigamonti et al., Phys. Rev. Lett. 114, 146402 (2015).

Type:	choose from: RPA LRCstatic_NLF LRCstatic LRCdyn_NLF LRCdyn ALDA MB1_NLF MB1 BO BO_SCALAR RBO
Default:	"RPA"
Use:	optional
XPath:	/input/xs/tddft/@fxctype

Attribute: intraband

By setting it to "true", the intraband contribution is included in the calculation for the finite q.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tddft/@intraband

Attribute: kerndiag

Set to "true" if only diagonal part of xc-kernel is to be used.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tddft/@kerndiag

Attribute: lindhard

Set to "true" if Lindhard-like function is to be calculated.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tddft/@lindhard

Attribute: lmaxalda

Angular momentum cutoff for Rayleigh expansion of exponential factor for ALDA-kernel.

Type:	integer
Default:	"3"
Use:	optional
XPath:	/input/xs/tddft/@lmaxalda

Attribute: mdfqtype

Treatment of macroscopic dielectric function for ${\bf Q}$-point outside of Brillouin zone. A value of 0 uses the full ${\bf Q}$ and the $({\bf 0},{\bf 0})$ component of the microscopic dielectric matrix is used. A value of 1 invokes a decomposition ${\bf Q}={\bf q}+{\bf G}_{\bf q}$ and the $({\bf Q}_{\bf q},{\bf Q}_{\bf q})$ component of the microscopic dielectric matrix is used.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/tddft/@mdfqtype

Attribute: nwacont

Number of energy intervals (on imaginary axis) for analytic continuation.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/tddft/@nwacont

Attribute: torddf

Set to "true" if to consider the time-ordered version of the dielectric function.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tddft/@torddf

Attribute: tordfxc

Set to "true" if to consider the time-ordered version of xc kernel (MBPT derived kernels only).

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tddft/@tordfxc

Element: screening

Type:	no content
XPath:	/input/xs/screening

This element allows for specification of the following attributes: do, intraband, nempty, ngridk, nosym, qpointsgamma, reducek, rgkmax, screentype, tr, vkloff

Attribute: do

Decides if the calculation of the screening is done from scratch or is to be skipped.

Type:	choose from: fromscratch skip
Default:	"fromscratch"
Use:	optional
XPath:	/input/xs/screening/@do

Attribute: intraband

Set to "false" to not use transition between states at same n but different k. Note: If the unit cell used in the calculation is not primitive, the n index does not corresponds to then physical band index due to the umklapp process at the cell boundaries.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/screening/@intraband

Attribute: nempty

Number of empty states.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/screening/@nempty

Attribute: ngridk

${\mathbf k}$-point grid sizes for screening.

Type:	integertriple
Default:	"0 0 0"
Use:	optional
XPath:	/input/xs/screening/@ngridk

Attribute: nosym

nosym is "true" if no symmetry information should be used for screening.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/screening/@nosym

Attribute: qpointsgamma

Is "true" if the dielectric matrix is only to be computed on the q-vectors relevant in a dense k-grid.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/screening/@qpointsgamma

Attribute: reducek

reducek is "true" if ${\mathbf k}$-points are to be reduced with crystal symmetries for screening.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/screening/@reducek

Attribute: rgkmax

The smallest muffin-tin radius times gkmax for screening.

Type:	fortrandouble
Default:	"0.0d0"
Use:	optional
XPath:	/input/xs/screening/@rgkmax

Attribute: screentype

Defines which type of screening is to be used.

Type:	choose from: full diag noinvdiag longrange
Default:	"full"
Use:	optional
XPath:	/input/xs/screening/@screentype

Attribute: tr

tr is "true" if the time reversal symmetry is used to equate the anit-resonant with the resonant part of Chi0 in the case of static screening without broadening.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/screening/@tr

Attribute: vkloff

${\mathbf k}$-point offset for screening.

Type:	vect3d
Default:	"-1.0d0 -1.0d0 -1.0d0"
Use:	optional
XPath:	/input/xs/screening/@vkloff

Element: BSE

Type:	no content
XPath:	/input/xs/BSE

This element allows for specification of the following attributes: aresbse, blocks, brixshdf5, bsedirsing, bsetype, checkposdef, chibar0, chibar0comp, chibarq, coupling, cuttype, distribute, econv, eecs, efind, fbzq, iqmtrange, lmaxdielt, measure, nexc, ngridksub, nleblaik, nosym, nstlbse, nstlxas, outputlevel, reducek, rgkmax, sciavbd, sciavqbd, sciavqhd, sciavqwg, sciavtype, scrherm, solver, vkloff, xas, xasatom, xasedge, xasspecies, xes

Attribute: aresbse

Is set to "true" if to consider the anti-resonant part for the BSE spectrum.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/BSE/@aresbse

Attribute: blocks

Defines which blocks of the BSE Hamiltonian are to be set up (resonant-resonat, resonant-anti-resonant or both).

Type:	choose from: rr ra both
Default:	"both"
Use:	optional
XPath:	/input/xs/BSE/@blocks

Attribute: brixshdf5

Set to true if you need output for BRIXS.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@brixshdf5

Attribute: bsedirsing

"true" if effective singular part of direct term of BSE Hamiltonian is to be used.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@bsedirsing

Attribute: bsetype

Defines which parts of the BSE Hamiltonian are to be considered.

Type:	choose from: IP RPA singlet triplet
Default:	"singlet"
Use:	optional
XPath:	/input/xs/BSE/@bsetype

Attribute: checkposdef

Set to "true" to check positive definitness of the auxilliary matrix used in BSE+TI.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@checkposdef

Attribute: chibar0

When chibar0 is "false", the full polarizability is calculated at q=0, otherwise the reduced polarizability is determined.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/BSE/@chibar0

Attribute: chibar0comp

Direction for calculation of dielectric function at q=0.

Type:	integer
Default:	"1"
Use:	optional
XPath:	/input/xs/BSE/@chibar0comp

Attribute: chibarq

Set to "true" to use the modified $\bar{\chi}$ also for finite q.

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/BSE/@chibarq

Attribute: coupling

Set to "true" to perform BSE without Tamm-Dancoff approximation.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@coupling

Attribute: cuttype

Defines how the Coulomb potential is to be truncated. Used for lower dimentional systems.

Type:	choose from: none 0d 2d
Default:	"none"
Use:	optional
XPath:	/input/xs/BSE/@cuttype

Attribute: distribute

Use ScaLAPACK or not.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@distribute

Attribute: econv

Additional energy for KS transitions to be included in the construction of the BSE hamiltoninan. Spectrum for a desired energy window needs to be converged with respect to this parameter. First/second entry is convergence energy for the lower/upper end of the spectrum.

Type:	vect2d
Default:	"0.0d0 0.0d0"
Use:	optional
XPath:	/input/xs/BSE/@econv

Attribute: eecs

Estimated BSE eigenvalue cluster size.

Type:	integer
Default:	"3"
Use:	optional
XPath:	/input/xs/BSE/@eecs

Attribute: efind

Set to "true" to solve the BSE Hamiltonian only for needed solutions with respect to desired energy window.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@efind

Attribute: fbzq

Set to "true" if q-point set is to be taken from the first Brillouin zone.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@fbzq

Attribute: iqmtrange

For which points in the q-point list should the BSE Matrix be constructed. A value of iqmtrange(1)=-1 uses all listed Q-points.

Type:	integerpair
Default:	"1 1"
Use:	optional
XPath:	/input/xs/BSE/@iqmtrange

Attribute: lmaxdielt

Angular momentum cutoff of the spherical harmonics expansion of the dielectric matrix.

Type:	integer
Default:	"14"
Use:	optional
XPath:	/input/xs/BSE/@lmaxdielt

Attribute: measure

Set to "true" to write out measures for the resonant-anti-resonat coupling.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@measure

Attribute: nexc

Number of excitons (eigensolutions) to be considered in a BSE calculation. The default corresponds to all.

Type:	integer
Default:	"-1"
Use:	optional
XPath:	/input/xs/BSE/@nexc

Attribute: ngridksub

The sub-grid of a BSE double grid run. Any value larger than 1 triggers a computation following this scheme: the BSE is solved several times on coarse grids, as given by ngridk and ngridq, which are shifted to all symmetry non-equivalent points of the sub-grid. The latter are distributed uniformly between the k-points of the coarse grid. The final results are obtained by averaging all the spectra yielded in this way, what is expected to be almost as good as solving the BSE on the fine grid, at much less computational cost.

Type:	integertriple
Default:	"1 1 1"
Use:	optional
XPath:	/input/xs/BSE/@ngridksub

Attribute: nleblaik

Number of points used for the Lebedev-Laikov grids must be selected according to V.I. Lebedev, and D.N. Laikov, Doklady Mathematics, 59 (1999) 477.

Type:	integer
Default:	"5810"
Use:	optional
XPath:	/input/xs/BSE/@nleblaik

Attribute: nosym

Set to "true" if no symmetry information should be used for BSE.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@nosym

Attribute: nstlbse

Range of bands included for the BSE calculation. The first pair of numbers corresponds to the band index for local orbitals and valence states (counted from the lowest eigenenergy), the second pair corresponds to the band index of the conduction states (counted from the Fermi level).

Type:	integerquadrupel
Default:	"0 0 0 0"
Use:	optional
XPath:	/input/xs/BSE/@nstlbse

Attribute: nstlxas

Range of bands included for the BSE calculation. The pair corresponds to the band index of the conduction states (counted from the Fermi level).

Type:	integerpair
Default:	"0 0"
Use:	optional
XPath:	/input/xs/BSE/@nstlxas

Attribute: outputlevel

Specify amount of information which is printed to files:

• normal - (default) standard information
• exper - detailed output

Type:	choose from: normal expert
Default:	"normal"
Use:	optional
XPath:	/input/xs/BSE/@outputlevel

Attribute: reducek

reducek is "true" if ${\mathbf k}$-points are to be reduced with crystal symmetries for BSE.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@reducek

Attribute: rgkmax

Smallest muffin-tin radius times gkmax.

Type:	fortrandouble
Default:	"0.0d0"
Use:	optional
XPath:	/input/xs/BSE/@rgkmax

Attribute: sciavbd

"true" if the body of the screened Coulomb interaction is to be averaged (q=0).

Type:	boolean
Default:	"true"
Use:	optional
XPath:	/input/xs/BSE/@sciavbd

Attribute: sciavqbd

"true" if the body of the screened Coulomb interaction is to be averaged (q!=0).

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@sciavqbd

Attribute: sciavqhd

"true" if the head of the screened Coulomb interaction is to be averaged (q!=0).

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@sciavqhd

Attribute: sciavqwg

"true" if the wings of the screened Coulomb interaction are to be averaged (q!=0).

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@sciavqwg

Attribute: sciavtype

Defines how the screened Coulomb interaction matrix is to be averaged (important for the singular terms).

Type:	choose from: spherical screendiag invscreendiag
Default:	"spherical"
Use:	optional
XPath:	/input/xs/BSE/@sciavtype

Attribute: scrherm

Method of how an almost Hermitian matrix is inverted. A value of 0: invert full matrix (matrix is allowed to be not strictly Hermitian); a value of 1: take the Hermitian average for inversion; a value of 2: assume Hermitian and use the upper triangle; a value of 3: assume Hermitian and use the lower triangle.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/BSE/@scrherm

Attribute: solver

Solver that is used to solve BSE:

• direct - setup full Hamiltonian and diagonalize it directly.
• fastBSE - fastBSE solver.

Type:	choose from: direct fastBSE
Default:	"direct"
Use:	optional
XPath:	/input/xs/BSE/@solver

Attribute: vkloff

${\mathbf k}$-point offset for BSE.

Type:	vect3d
Default:	"-1.0d0 -1.0d0 -1.0d0"
Use:	optional
XPath:	/input/xs/BSE/@vkloff

Attribute: xas

Set to "true" to perform BSE X-rasy absorption spectroscopy (XAS) calculation

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@xas

Attribute: xasatom

Atom number for which the XAS is calculated.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/BSE/@xasatom

Attribute: xasedge

Defines the initial states of the XAS calculation.

Type:	choose from: K L1 L2 L3 L23 M1 M2 M3 M23 M4 M5 M45 N1 N2 N3 N23 N4 N5 N45
Default:	"K"
Use:	optional
XPath:	/input/xs/BSE/@xasedge

Attribute: xasspecies

Species number for which the XAS is calculated.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/BSE/@xasspecies

Attribute: xes

Set to "true" to perform BSE X-rasy emission spectroscopy (XES) calculation

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/BSE/@xes

Element: fastBSE

Type:	no content
XPath:	/input/xs/fastBSE

This element allows for specification of the following attributes: clanczos, cvtsteplim, cvttol, ngridr, nisdf, nlanczos, saveQ, seed

Attribute: clanczos

Define the number of Lanczos iterations by the portion $c$ of the BSE Hamiltonian size $n_\text{BSH}$ such that $n_\text{Lanczos} = c \cdot n_\text{BSH}$. If the element nlanczos is given ($> 0$), this element is ignored.

Type:	fortrandouble
Default:	"0.01"
Use:	optional
XPath:	/input/xs/fastBSE/@clanczos

Attribute: cvtsteplim

Number sub matrix size

Type:	integer
Default:	"100"
Use:	optional
XPath:	/input/xs/fastBSE/@cvtsteplim

Attribute: cvttol

Tolerance for deciding if the cluster centroids are element wise the same as in the previous CVT step.

Type:	fortrandouble
Default:	"1e-2"
Use:	optional
XPath:	/input/xs/fastBSE/@cvttol

Attribute: ngridr

Sampling of the real space grid for calculating the wavefunctions on.

Type:	integertriple
Default:	"5 5 5"
Use:	optional
XPath:	/input/xs/fastBSE/@ngridr

Attribute: nisdf

Number ISDF interpolation points for the wavefunction pair product. The first value is used for the exchange interaction kernel, The second and third for pairs of occupied and unoccupied wavefunctions respectly, used for the calculation of the screened interaction kernel.

Type:	integertriple
Default:	"10 10 10"
Use:	optional
XPath:	/input/xs/fastBSE/@nisdf

Attribute: nlanczos

Number Lanczos iterations

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/fastBSE/@nlanczos

Attribute: saveQ

Save transformation matrix $Q_k$ from the Lanczos iterations.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/fastBSE/@saveQ

Attribute: seed

Specify the solver type for solving the BSE:

• clock - (default) Seed random number generation with the system time.
• fixed - Use always the same seed (for testing).

Type:	choose from: clock fixed
Default:	"clock"
Use:	optional
XPath:	/input/xs/fastBSE/@seed

Element: transitions

Describe transitions between Kohn-Sham states for the calculation of the Kohn-Sham response function (and screening) here. Individual transitions as well as a range (or a list) of initial and final states can be defined.

contains:	individual (optional) ranges (optional) lists (optional)
XPath:	/input/xs/transitions

Element: individual

A list of individual transitions consisting of an initial state a final state and a ${\mathbf k}$-point is given here. If the list is empty, no transitions are considered.

contains:	trans (optional)
XPath:	/input/xs/transitions/individual

Element: trans

An individual transition consisting of an initial state a final state and a ${\mathbf k}$-point is given here. Values of zero correspond to the inclusion of all initial and final states and all ${\mathbf k}$-points and can be used as "wildcards" (default). Therefore, an empty element amounts to include all transitions.

Type:	no content
XPath:	/input/xs/transitions/individual/trans

This element allows for specification of the following attributes: action, final, initial, kpointnumber

Attribute: action

Select to include or exclude states. If a state is included as well as excluded several times the last definition (in the sequence of individual transitions) counts.

Type:	choose from: include exclude
Default:	"include"
Use:	optional
XPath:	/input/xs/transitions/individual/trans/@action

Attribute: final

Final state of individual transition. A value of zero (default) means to include all states.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/transitions/individual/trans/@final

Attribute: initial

Initial state of individual transition. A value of zero (default) means to include all states.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/transitions/individual/trans/@initial

Attribute: kpointnumber

Number of ${\mathbf k}$-points to be considered. A value of zero (default) means to include all ${\mathbf k}$-points.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/transitions/individual/trans/@kpointnumber

Element: ranges

A list of ranges of transitions (initial state as well as final state ranges) and a ${\mathbf k}$-point are given here. An empty list amounts to no transitions at all.

contains:	range (optional)
XPath:	/input/xs/transitions/ranges

Element: range

A range of transitions (for initial as well as final states) is given here. A range consists of a "start" and a "stop" values as well as a ${\mathbf k}$-point. Values of zero correspond to starting at the first state and stopping at the last state and considering all ${\mathbf k}$-points. They can be used as "wildcards" (default). Therefore, an empty element corresponds to the full initial/final state range for all ${\mathbf k}$-points.

Type:	no content
XPath:	/input/xs/transitions/ranges/range

This element allows for specification of the following attributes: statestype (required), action, kpointnumber, start, stop

Attribute: action

Select to include or exclude states. If a state is included as well as excluded several times the last definition (in the sequence of individual transitions) counts.

Type:	choose from: include exclude
Default:	"include"
Use:	optional
XPath:	/input/xs/transitions/ranges/range/@action

Attribute: kpointnumber

Number of ${\mathbf k}$-point to be considered. A value of zero (default) means to include all ${\mathbf k}$-point.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/transitions/ranges/range/@kpointnumber

Attribute: start

Start value (first state) for range. A value of zero (default) means to start from the first state.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/transitions/ranges/range/@start

Attribute: statestype

Select for initial or final state range.

Type:	choose from: initialstates finalstates
Use:	required
XPath:	/input/xs/transitions/ranges/range/@statestype

Attribute: stop

Stop value (last state) for range. A value of zero (default) means to stop at the last state (no upper limit).

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/transitions/ranges/range/@stop

Element: lists

A list of initial and final state entries to be considered for transitions. An empty list amounts to no transitions at all.

contains:	istate (optional)
XPath:	/input/xs/transitions/lists

Element: istate

An initial or final state and corresponding ${\mathbf k}$-point is given here. Values of zero correspond to considering all initial/final states for all ${\mathbf k}$-points. They can be used as "wildcards" (default). Therefore, an empty element corresponds to the full initial/final state set for all ${\mathbf k}$-points.

Type:	no content
XPath:	/input/xs/transitions/lists/istate

This element allows for specification of the following attributes: statestype (required), action, kpointnumber, state

Attribute: action

Select to include or exclude states. If a state is included as well as excluded several times the last definition (in the sequence of individual transitions) counts.

Type:	choose from: include exclude
Default:	"include"
Use:	optional
XPath:	/input/xs/transitions/lists/istate/@action

Attribute: kpointnumber

Number of ${\mathbf k}$-point to be consider. A value of zero (default) means to include all ${\mathbf k}$-point.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/transitions/lists/istate/@kpointnumber

Attribute: state

The state to be considered. A value of zero (default) means to include all states.

Type:	integer
Default:	"0"
Use:	optional
XPath:	/input/xs/transitions/lists/istate/@state

Attribute: statestype

Select for initial or final state list.

Type:	choose from: initialstates finalstates
Use:	required
XPath:	/input/xs/transitions/lists/istate/@statestype

Element: tetra

Type:	no content
XPath:	/input/xs/tetra

This element allows for specification of the following attributes: cw1k, kordexc, qweights, tetradf, tetraocc

Attribute: cw1k

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tetra/@cw1k

Attribute: kordexc

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tetra/@kordexc

Attribute: qweights

Choice of weights and nodes for the tetrahedron method and non-zero Q-point.

Type:	integer
Default:	"1"
Use:	optional
XPath:	/input/xs/tetra/@qweights

Attribute: tetradf

"true" if tetrahedron method is used for the ${\mathbf k}$-space integration in the Kohn-Sham response function.

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tetra/@tetradf

Attribute: tetraocc

Type:	boolean
Default:	"false"
Use:	optional
XPath:	/input/xs/tetra/@tetraocc

Element: plan

contains:	doonly (optional)
XPath:	/input/xs/plan

Element: doonly

Type:	no content
XPath:	/input/xs/plan/doonly

This element allows for specification of the following attributes: task (required)

Attribute: task

Type:	choose from: xsgeneigvec tetcalccw writepmatxs writeemat planewave_elements df df2 idf scrgeneigvec scrtetcalccw scrwritepmat screen phonon_screening expand_add_eps write_dielectric_matrix write_screened_coulomb scrcoulint exccoulint bse bsegenspec writebevec writekpathweights bsesurvey kernxc_bse writebandgapgrid write_screen writepmat dielectric fastBSE_main fastBSE_human_readable_output fastBSE_groundstate_properties fastBSE_isdf_cvt writepmatasc pmatxs2orig writeoverlapxs write_pmat_hdf5_xs writeematasc writepwmat emattest x0toasc x0tobin fxc_alda_check kernxc_bse3 testxs xsestimate testmain excitonWavefunction portstate(1) portstate(2) portstate(-1) portstate(-2)
Use:	required
XPath:	/input/xs/plan/doonly/@task

Reused Elements

The following elements can occur more than once in the input file. There for they are listed separately.

Data Types

The Input definition uses derived data types. These are described here.